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50ohm headphones (Fostex T50rp)...is that an issue

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lorriman

New Member
50ohm headphones (Fostex T50rp)...is that an issue?

I've understood that HP sockets on integrated amps/receivers do no favours for headphones rated at less than 120 ohms: that I would be better off getting a (cheap?) cmoy. My phones require a lot of power but have lowish ohms, at 50. However they are orthos and I was wondering if that might compensate in some way.

Or perhaps there are integrateds or receivers that work well as HP amps and have a lower spec for headphone ohmage? I would love some recomendations. I'm in the UK so my choice of quality amps stretches to rotel, kenwood, Denon and pioneer (not forgetting yamaha and sony; I just don't hear much of them). There aren't any Marantz's or Sansui's here.

As a third possibility: might I be able to rig up some kind of gadget to adjust the HP socket to make it more friendly to my orthos? Or perhaps I could dissemble the HP socket and put some resisters in to it? I'm handy with a solder but know absolutely nothing about electronics.
 
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50 ohms should not be an issue for vintage receivers (e,g, 1980 and earlier) and probably newer ones too. The only amps I know that have trouble with low impedance cans are tube based and output transformerless.
 
The problem with using receivers is that they have a high output impedance, that would most likely be many times as high as the headphones impedance, this could cause dampening issues.
 
Thanks for the replies. I did understand that they would work but what I'm concerned with is whether there would be a significant loss of quality.

Adda said:
The problem with using receivers is that they have a high output impedance, that would most likely be many times as high as the headphones impedance, this could cause dampening issues.
Click to expand...

Are you mentioning receivers particularly as opposed to integrated amps? Would I be better avoiding receivers?
 
The T50Rp's are one of my favorite headphones once modified but they do like a little power. They work extremely well with vintage receivers and integrated amplifiers that operate the headphone jack from the actual amplifier itself. They will sound like ass from a lot of more modern headphone jacks that use a very basic opamp setup.
 
FYI: Most older integrated amps and receivers simply fed the headphone jack directly from the speaker outputs, via a few 50 to 100 ohm padding resistors.
Op-Amps at the time thankfully weren't even a consideration or option.
 
Thanks for that BmWr75, but It's just too long and liable not to answer my question (I've already tried googling head-fi for this issue).

Vaughn, that's great to know.
 
lorriman said:
Thanks for that BmWr75, but It's just too long and liable not to answer my question (I've already tried googling head-fi for this issue).
Click to expand...

Granted that is a long thread, sorry about that.

Bottom-line: buy a 70s vintage receiver or integrated that is in good shape (recapped preferably) and you should be good to go.

Alternatively, you can buy a solid state Matrix m-stage headphone amp for $270 including shipping on Amazon.com (from TAM Audio, the reliable Matrix shipper in China) and be set also.
 
Thanks for the advice, guys.

Any word on a minimum power requirement for the Fostex? For example would it be fine to go for a cheapo 20W Rotel amp? I don't expect to get one of those; simply sounding out the limit.
 
You already got our answer here:

http://www.head-fi.org/t/537704/calling-all-vintage-integrated-receiver-owners/2835#post_7795369

At the risk of starting to beat a dead horse........cheap, low power receivers made after the early 1980s are generally not going to be optimum for headphones.

If conserving electricity is really a concern and $100 is within the budget, check this out. It is the top rated portable amp on Head-Fi.org:

http://www.head-fi.org/products/electric-avenues-pa2v2

http://www.electric-avenues.com/amplifiers.html
 
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BmWr75 said:
You already got our answer here:

http://www.head-fi.org/t/537704/calling-all-vintage-integrated-receiver-owners/2835#post_7795369
Click to expand...

Sure, but opinions vary. Of course it doesn't help if all the same people are in both forums; but I doubt that's true of everyone.

At the risk of starting to beat a dead horse........cheap, low power receivers made after the early 1980s are generally not going to be optimum for headphones.
Click to expand...

I'm assuming that this isn't true of Rotels which is what I'm most likely to get; or perhaps I should say 'cheaper' Rotel. I have the impression that I won't be fobbed off with an opamp if I get a Rotel, even a cheap one. The issue for me of very old kit, that you mention, is the need to get a service. I am actually handy with a solder but warnings of "unless you know exactly what you are doing don't due to high voltages" have rather put me off the idea replacing all their caps myself. I don't wish to acquire a harp just yet. But I can't really afford a service.

If conserving electricity is really a concern and $100 is within the budget, check this out. It is the top rated portable amp on Head-Fi.org:

http://www.head-fi.org/products/electric-avenues-pa2v2

http://www.electric-avenues.com/amplifiers.html
Click to expand...

I love stuff like that. I can't justify it however, unless it really is impossible to get lower power integrated/receivers. Right now I am assuming that a 30W amp uses 30 watts of power, which is less than a light bulb. The reason I mention it is because that assumption may be completely wrong and infact unbeknown to me I may be burning 500 watts, which is way too much. That would come to 7p an hour which over a year would be £50 instantly justifying that headphone amp.

Thanks for the great advice.
 
50 ohm headphones are a bit low for a CMoy especially if they are low efficiency. The chip will current limit and distort at relatively low volume. Most older amps would have been designed to drive 8 ohm headphones so, on paper, 50 ohm phones shouldn't be a problem however they may not provide much drive.
 
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